Transient hole currents in hydrogenated amorphous silicon at low temperatures and high fields

Abstract

Abstract Low-temperature high-field properties of hole transport have been investigated by transient photoconductivity experiments on undoped hydrogenated amorphous silicon. The hole μτproduct at 80K is roughly 7 × 10−10 cm 2 V−1 and the hole mobility 9 × 10−3 cm 2 V−1 s−1 or greater at about 105Vcm−1. The dispersion parameter αD calculated from the slope of the post-transit decay increases from 0 at F< 105Vcm−1 to about 0·4 for F = 2.5 × 105 Vcm−1. The data are discussed in terms of field-stimulated hopping in the valence-band tail and an analytic interpretation of the characteristic current decay is introduced. The data demon-strate the large influence of the field on hole propagation at low temperatures.